1. Field of the Invention
The present invention relates to a manufacturing method of an alkaline solution for developing and removing a resist film, and the like and the alkaline solution, a pattern forming method using the alkaline solution, a removing method of a resist film, a solution application apparatus, a substrate treatment method prior to forming the resist film, and a solution supplying method of scanning a linear solution supply nozzle from one end to the other end of a substrate, and supplying the solution onto the substrate from the solution supply nozzle to form a solution film on the substrate.
2. Description of the Related Art
With the miniaturization of semiconductor elements and enlargement of a diameter of a substrate, in a conventional developing method, generation of a critical defect resulting from development, variation of a pattern size in a substrate surface and chip, and the like raise large problems.
In general, in a semiconductor manufacturing process, aqueous solutions such as alkaline tetramethyl ammonium hydroxide (TMAH) are used as a developing solution for a photosensitive resist film. Since the developing solution is an aqueous solution, wettability is not sufficient with respect to a photosensitive resist surface having a hydrophobic property. Therefore, when a reaction product resulting from neutralization is in the vicinity of the resist film surface, the developing solution is not easily diffused between the reaction product and the photosensitive resist surface. As a result, the reaction product cannot sufficiently be removed by pure water in a rinse process, and remains on the substrate and disadvantageously produces a defect.
Moreover, in a pattern disposed in a broad dissolution region, the amount of reaction products present in the vicinity of the pattern is large. Therefore, the developing solution is not easily diffused between the reaction product and the photosensitive resist film, and a progress of development is hindered. Therefore, for the pattern disposed in the broad dissolution region, as compared with a pattern disposed in a region whose periphery is hardly dissolved, there is a problem that a line size is increased.
It has previously been possible to solve these problems to some degree by using a developing solution with a surface-active agent added thereto to enhance affinity of the photosensitive resist surface for the developing solution. However, with the reduction in exposure wavelength, it has been necessary to maintain transparency/etching resistance of a resin in a short wavelength band, and a photosensitive resist material having a strong interaction between resins has been used. Therefore, when the developing solution with the surface-active agent added thereto is used, the wettability with the photosensitive resist film surface can be enhanced only to a certain degree. As a result, problems occur that defects are generated and a size difference is brought in a sparse/dense pattern.
Additionally, with the size miniaturization of the semiconductor element and the enlargement of the diameter of the substrate, in the conventional method, a size variation of the pattern in the substrate surface and chip, which is said to result from the development, raises a large problem. As a countermeasure, a technique of scanning a linear nozzle from one end to the other end of the substrate and forming a solution film evenly on the whole surface of the substrate has been proposed (Jpn. Pat. Appln. KOKAI Publication Nos. 10-303103 and 10-189419).
In the technique described in the Jpn. Pat. Appln. KOKAI Publication Nos. 10-303103 and 10-189419, it is disclosed that a gap between a supply position of the nozzle and the substrate is 0.3±0.1 mm, a flow rate of the developing solution is set to 1.5 L/min., a scanning speed of the nozzle is set to 10 to 500 mm/second and the solution film is formed. However, even when the solution film is formed in these conditions, the formed solution film thickness is not necessarily equal to the gap. Therefore, a size difference is disadvantageously produced in a substrate plane and chip depending on a subtle flow of the solution generated during the application of the solution. Concretely, since the formed solution film thickness is not equal to the gap, a subtle solution flow is generated during the application of the solution. When a dissolution region exists upstream of a solution flow, the etching speed drops due to an influence of reaction products. Conversely, when the upstream of solution flow is a non-dissolution region, the etching speed rises due to the fresh developing solution.
As described above, the photosensitive resist having a strong interaction between resins has been used, the defects are generated, and a size difference is disadvantageously produced in the sparse/dense pattern.
Moreover, in the technique of scanning a linear nozzle from one end to the other end of a substrate and forming a solution film evenly on the whole surface of the substrate, the size dispersion is disadvantageously produced in a substrate plane and chip due to the subtle solution flow generated during the application of the solution.